A magnetoresistance sensing device includes a substrate, a magnetoresistance sensing unit, and a magnetic field adjusting unit. A programmed microprocessor calculates the length of flexible packaging material needed to package the product based on the physical dimensions of the product, calculates the weight of the flexible packaging material needed, and calculates a total package weight as the sum of the weight of the product and the calculated weight of the flexible packaging material. With reference to calibration tables, each of which correlates one of a pixel position on a coordinate system of each corrected image and information having a predetermined relation to the pixel position with information specifying a direction and a position of incident light traveling to the pixel position, the direction and the position of the incident light are obtained. The digital interpolator supplies the phases using a double clocked shift register with recirculating feedback. The control module generates an engine position synchronization signal based on the transitioning. The vestibule has at least two doors, one interior door and one exterior door, that allow people to enter and leave the aviary while keeping the animals securely housed within the main room, away from the exterior door of the aviary.